Notes

• non specific= the same response regardless of the pathogen
• inflammation

  • body cells respond to tissue damage, secrete chemical signalling molecule HISTAMINE- aids communication
  • causes vasodilation of arterioles which increases blood flow through capillaries to the site of infection= redness
  • cappilary walls also more permeable/leaky- allowing blood plasma to leave capillaries and enter tissue causing swelling
  • phagocytes enter tissue to engluf foreign pathogens
• cytokines

  • cells also release cytokines
  • another cell signalling molecule triggering immune response in infected area
• interferons

  • cells infected by viruses produce anti-viral proteins called interferons
  • prevent virus spreading to uninfected cells:

  -inhibit production of viral proteins, stop virus replicating

  -activates white blood cells involved with specific immune response, to destroy infected cells

  -increases non specific immune response eg promoting inflammation
• phagocytosis

  -engulfing and destroying pathogens

  1. chemicals released by pathogens and body cells under attack (eg histamine) attracts phagocytes to pathogen location
  2. phagocytes recognise non self antigens, cell membrane of phagocyte extends out and around pathogen, engulfing it in phagocytic vacuole(endocytosis)
  3. enzymes released into phagocytic vacuole when lysosome fuse with it- digestive enzymes digest the pathogen
  4. after digesting- phagocyte presents antigen of pathogen on its cell surface membrane=APC- initiates specific immune response